intrinsic discolouration 2 Flashcards
how long does at home whitening usually take to see full effects
around 3-6 weeks
discuss the mechanism of external tooth bleaching with hydrogen peroxide
hydrogen peroxide is a strong oxidising agent capable of producing oxygen and perhydroxyl free radicals
These highly reactive radicals penetrate the organic component of enamel and dentine and
highly pigmented carbon ring compounds are opened and converted into chains of lighter colour
existing C=C bons compounds usually yellow in colour are converted into hydroxyl groups which are colourless
indications for vital bleaching
generalised orange/yellow/ light brown discolouration
age related yellow staining
mild tetracycline staining
superficial brown fluorosis stains
discolouration due to smoking, tea etc
patients with genetically yellow or grey teeth
yellow discolouration of single vital anterior tooth
contraindications for vital bleaching
amelogenesis and dentogenesis imperfecta
severe tetracycline discolouration
discolouration due to restorative materials e.g amalgam
pregnant or breastfeeding
severe toothwear
severe pre existing sensitivity
unrealistic expectations
discuss the breakdown and byproducts of 10% carbamide peroxide
10% of carbamide peroxide produces 3% hydrogen peroxide and 7% urea which breakdown to form water, ammonia and carbon dioxide
how much root filling should be removed prior to commencing non vital bleaching
root filling removed to below gingival margin to allow adequate bleaching of cervical area
what are the two methods of non vital tooth bleaching
walking bleach
inside out bleaching
what is the walking bleach technique of non vital bleaching
bleaching agent placed into pulp chamber and sealed off with temporary material
patient returns to surgery every 2 weeks to have bleach renewed
what is the inside out bleaching technique of non vital bleaching
access cavity to tooth is left open
custom made mouthguard is created, patient applies bleaching agent into chamber and back of tray
relies on good OH and compliance
worn all the time except eating and cleaning
after bleaching is achieved in inside out bleaching, how should the tooth be restored
non setting calcium hydroxide paste should be placed for 2 weeks then seal with GIC to reverse any acidity in PDL which may have occured if bleaching agent seeped
then either white GP and composite or incrementally cured composite (harder to retreat)
potential complications of non vital bleaching
external cervical root resorption
spillage of bleaching agents
failure to bleach
over bleach
brittleness of tooth crown
what is external cervical root resorption in reference to non vital bleaching
mechanism not fully understood
bleaching material may diffuse through dentinal tubules into PDL and initiate an inflammatory action which stimulates osteoclast activity leading to resorption
what steps can be taken to prevent external cervical root resorption in non vital bleaching
layer of cement over GP prior to introduction of bleaching agent to prevent bleach reaching external surface of root
(may prevent adequate bleaching of cervical area)
discuss tooth mousse
best benefits are for caries prevention and sensitivity
limited evidence supporting its use for aesthetic improvement
contains milk proteins
manufacturer suggests using it as an adjunct to microabrasion and bleaching
expensive for patient
discuss resin infiltration
infiltration of enamel lesions with low viscosity light curing lesions
surface layer is eroded, lesions dessicated and resin infiltrant applied
infiltrated lesions lose discoloured appearance
(resin infiltrate driven by capillary forces)
